finish eight

app/eight.hs

@@ -0,0 +1,61 @@
+import           Data.Char
+
+type TreeHeight=Int
+data Tree = Tree TreeHeight [TreeHeight] [TreeHeight] [TreeHeight] [TreeHeight] deriving(Show)
+
+parseTrees :: [[TreeHeight]] -> [TreeHeight] -> [[TreeHeight]] -> [Tree]
+parseTrees linesAbove heights linesBelow = do
+  let heightsWithIndex = zipWith (,) heights [0..]
+  let trees=map (\heightWithIndex -> do
+          let (_,columnAbove) = getAlingedHeightsInColumn (linesAbove) heightWithIndex
+          let (_,columnBelow) = getAlingedHeightsInColumn linesBelow heightWithIndex
+          let (rowBefore,self:rowAfter) =  splitAt (snd heightWithIndex) heights
+          Tree (fst heightWithIndex) columnAbove columnBelow (reverse rowBefore) rowAfter ) heightsWithIndex
+  let recrusiveResult = if (0 == length linesBelow) then [] else
+                           (parseTrees (heights:linesAbove) (head linesBelow ) $ tail linesBelow)
+  trees <> recrusiveResult
+
+isVisible :: Tree -> Bool
+isVisible (Tree height columnAbove columnBelow rowBefore rowAfter) =
+  canBeSeen columnAbove ||
+    canBeSeen columnBelow ||
+      canBeSeen rowBefore ||
+        canBeSeen rowAfter
+  where canBeSeen = all (< height)
+
+
+getTreeViewingScore :: Tree -> Int
+getTreeViewingScore (Tree height columnAbove columnBelow rowBefore rowAfter) =
+  foldl (*) 1 $ map (scoreInOneDirection height) [columnBelow,columnAbove,rowAfter,rowBefore]
+
+scoreInOneDirection :: TreeHeight ->  [TreeHeight] -> Int
+scoreInOneDirection height heights =let (a,b,c) = (foldl foldFunc (-1,0,True) heights) in b
+      where foldFunc :: (TreeHeight,Int,Bool) -> TreeHeight -> (TreeHeight,Int,Bool)
+            foldFunc (currentHeight,count,canSee) nextHeight
+              | not canSee = (currentHeight,count,canSee)
+              | nextHeight >= height = (currentHeight,count+1,False)
+              | nextHeight >= currentHeight = (max nextHeight currentHeight,count+1,True)
+              | nextHeight < currentHeight = (currentHeight,count+1,True)
+
+
+
+getAlingedHeightsInColumn :: [[TreeHeight]] -> (TreeHeight,Int) -> (TreeHeight,[TreeHeight])
+getAlingedHeightsInColumn rows ((ownHeight,index)) = (ownHeight, map (!! index) rows)
+
+mainP1:: IO ()
+mainP1 = do
+  content <- readFile "eight-input.txt"
+  let (firstRow:rest) = (map digitToInt) <$> lines content
+  let trees = parseTrees [] firstRow rest
+  print $ length  $ filter isVisible trees
+
+mainP2:: IO ()
+mainP2 = do
+  content <- readFile "eight-input.txt"
+  let (firstRow:rest) = (map digitToInt) <$> lines content
+  let trees = parseTrees [] firstRow rest
+  mapM (print) trees
+  print $ maximum $    map getTreeViewingScore trees
+
+
+main=mainP2